43,301 research outputs found
Towards a micropositioning system for targeted drug delivery in wireless capsule endoscopy
This paper describes a novel micropositioning mechanism for achieving 1ml of targeted drug delivery within wireless capsule endoscopes. The mechanism allows a needle to be positioned within a 22.5Ā° segment of a cylindrical capsule and be extendible by up to 4mm. The mechanism achieves both these functions using only a single micromotor and occupying a volume of just 200mmĀ³ (including micromotor), this represents only 6.6% of the total available space. Through a detailed stress analysis it has been shown that the proposed mechanism can be fabricated using FDA approved materials and requires a power budget of under 3.3% of the available capacity. It is envisaged this mechanism would empower a new breed of capsule microrobots for therapy in addition to diagnostics for pathologies such as ulcerative colitis and small intestinal Crohnās disease.Accepted versio
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Optimum projection angle for attaining maximum distance in a rugby place kick
This article has been made available through the Brunel Open Access Publishing Fund.This study investigated the effect of projection angle on the distance attained in a rugby place kick. A male rugby player performed 49 maximum-effort kicks using projection angles of between 20 and 50Ā°. The kicks were recorded by a video camera at 50 Hz and a 2 D biomechanical analysis was conducted to obtain measures of the projection velocity and projection angle of the ball. The player's optimum projection angle was calculated by substituting a mathematical expression for the relationship between projection velocity and projection angle into the equations for the aerodynamic flight of a rugby ball. We found that the player's calculated optimum projection angle (30.6Ā°, 95% confidence limits Ā± 1.9Ā°) was in close agreement with his preferred projection angle (mean value 30.8Ā°, 95% confidence limits Ā± 2.1Ā°). The player's calculated optimum projection angle was also similar to projection angles previously reported for skilled rugby players. The optimum projection angle in a rugby place kick is considerably less than 45Ā° because the projection velocity that a player can produce decreases substantially as projection angle is increased. Aerodynamic forces and the requirement to clear the crossbar have little effect on the optimum projection angle
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Analysis of two-operator boundary-domain integral equations for variable-coefficient mixed BVP
This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2011 Steklov Mathematical Institute RAS.Applying the two-operator approach, the mixed (DirichletāNeumann) boundary value problem for a second-order scalar elliptic differential equation with variable coefficients is reduced to several systems of Boundary Domain Integral Equations, briefly BDIEs. The two-operator BDIE system equivalence to the boundary value problem, BDIE solvability and the invertibility of the boundary-domain integral operators are proved in the appropriate Sobolev spaces.This research was supported by the IMU-AMMSI-ICMS-LMS Initiative āMentoring African Research in Mathematicsā funded by the Nuffield Foundation and the Leverhulme Trust
Computationally efficient modeling of proprioceptive signals in the upper limb for prostheses: a simulation study.
Accurate models of proprioceptive neural patterns could one day play an important role in the creation of an intuitive proprioceptive neural prosthesis for amputees. This paper looks at combining efficient implementations of biomechanical and proprioceptor models in order to generate signals that mimic human muscular proprioceptive patterns for future experimental work in prosthesis feedback. A neuro-musculoskeletal model of the upper limb with 7 degrees of freedom and 17 muscles is presented and generates real time estimates of muscle spindle and Golgi Tendon Organ neural firing patterns. Unlike previous neuro-musculoskeletal models, muscle activation and excitation levels are unknowns in this application and an inverse dynamics tool (static optimisation) is integrated to estimate these variables. A proprioceptive prosthesis will need to be portable and this is incompatible with the computationally demanding nature of standard biomechanical and proprioceptor modelling. This paper uses and proposes a number of approximations and optimisations to make real time operation on portable hardware feasible. Finally technical obstacles to mimicking natural feedback for an intuitive proprioceptive prosthesis, as well as issues and limitations with existing models, are identified and discussed
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Construction of a synthetic messenger RNA encoding a membrane protein.
We have synthesized microgram quantities of a functional eucaryotic mRNA by in vitro transcription. For this purpose, we constructed a plasmid in which the Escherichia coli lactose promoter was 5' to the vesicular stomatitis virus (VSV) G protein gene (Rose, J. K., and C. J. Gallione, 1981, J. Virol., 39:519-528). This DNA served as the template in an in vitro transcription reaction utilizing E. coli RNA polymerase. The RNA product was capped using the vaccinia guanylyltransferase. A typical preparation of the synthetic G mRNA was equivalent to the amount of G mRNA that can be isolated from approximately 10(8) VSV-infected cells. This synthetic mRNA was translated by a wheat germ extract in the presence of microsomes, producing a polypeptide that was indistinguishable from G protein in its size, antigenicity, degree of glycosylation, and its membrane insertion. This technique should aid in identifying features needed by proteins for insertion into membranes
An Ultra-Low-Power Front-End Neural Interface with Automatic Gain for Uncalibrated Monitoring
Accepted versio
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People, place and fish: Exploring the Cultural Ecosystem Services of Inshore Fishing through Photography
The Millennium Ecosystem Assessment (MEA, 2005) set out a framework for understanding the benefits that humans derive from the environment in order to inform decision making. It categorized these benefits as: provisioning services, such as food, water, timber; regulating services, such as climate control, waste, water quality; supporting services, such as soil formation, photosynthesis, nutrient cycling; and cultural services, such as recreational, spiritual and aesthetic benefits. Since then there has been a plethora of research and wider interest in devising ways of assessing and measuring those services (Haines-Young and Potschin, 2009; Sagoff, 2011; Shan and Swinton, 2011), often involving economic valuation techniques devised by economists and ecologists. While these can be useful for assessing the provisioning, supporting and regulating services, measuring or assessing the cultural services that humans receive from ecosystems has proved to be more problematic. However, there is increasing recognition of the role of multiple disciplines in understanding the complex and multi-faceted ways that ecosystems shape culture and cultural value
A compact targeted drug delivery mechanism for a next generation wireless capsule endoscope
This paper reports a novel medication release and delivery mechanism as part of a next generation wireless capsule endoscope (WCE) for targeted drug delivery. This subsystem occupies a volume of only 17.9mm3 for the purpose of delivering a 1 ml payload to a target site of interest in the small intestinal tract. An in-depth analysis of the method employed to release and deliver the medication is described and a series of experiments is presented which validates the drug delivery system. The results show that a variable pitch conical compression spring manufactured from stainless steel can deliver 0.59 N when it is fully compressed and that this would be sufficient force to deliver the onboard medication
Psychometric Properties of the Drive for Muscularity Attitudes Questionnaire Among Irish Men
The Drive for Muscularity Attitudes Questionnaire (DMAQ) was developed to measure menās desire to attain an idealized muscular body. To date, the cross-cultural suitability of this measure has received limited attention. The current study addressed this omission by testing the psychometric properties of the DMAQ using an online sample of Irish men ( N = 327). Confirmatory factor analysis revealed that a unidimensional model adequately matched observed data (i.e., fit indices suggested acceptable model fit). Analyses also showed that the DMAQ yielded reliable and construct valid scores, suggesting that the scale holds promise as an indicant of the drive for muscularity among Irish men. Strengths and limitations associated with this study are discussed, such as advantages and disadvantages of Internet research. Directions for future research are given, including the need for more psychometric wor
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